RFR(XS): 8214235: assertion in collectedHeap.cpp: attempt to clean empty remainder

Boris Ulasevich boris.ulasevich at bell-sw.com
Thu Nov 29 11:02:27 UTC 2018


Hi Per,

On 28.11.2018 17:35, Per Liden wrote:
> Hi,
> 
> On 11/28/18 1:39 PM, Boris Ulasevich wrote:
>> Hi all,
>>
>> Please review a simple fix: do not fill remaining tlab memory
>> when the remainder is empty.
> 
> Hmm I get the feeling something else is wrong here. Like a misaligned 
> object or a misaligned object size was allocated in the TLAB.

Actually assertion check catches the case when top() = end().
I do not think it is something criminal. May be it is better to
add check (top() < hard_end()) instead:
http://cr.openjdk.java.net/~bulasevich/8214235/webrev.00

> When you crash here it would be interesting to see what the tlab 
> start/end/top/etc is and what MinObjAlignement is being used.

TLAB: start()=0x938b0b28, end()=0x938dcdc8, top()=0x938dcdc8
MinObjAlignment: 2

> cheers,
> Per
> 
>>
>> https://bugs.openjdk.java.net/browse/JDK-8214235
>> http://cr.openjdk.java.net/~bulasevich/8214235/webrev.01
>>
>> Thanks,
>> Boris


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